Ceramidase

ABSTRACT

A ceramidase having the following structural motif 
     Z 1 -X1-H-X2-T-L-X2-X2-X2-X2-Q-X2-X2-D-E,-Z 2   
     wherein the X1 position is an aromatic amino acid (F, Y or W), all X2 positions may be any independent amino acids, and Z 1  and Z 2  may be any polypeptides.

[0001] The present invention relates to a ceramidase.

[0002] Ceramidase cleaves ceramide and produces sphingosine, which is subsequently further converted into sphingosine-1-phosphate. Various ceramidase activities have been described:

[0003] 1. an acid lysosomal ceramidase which further degrades the ceramide formed by acid sphingomyelinase;

[0004] 2. a non-acid membrane-bound ceramidase activity;

[0005] 3. secreted neutral and alkaline ceramidase activities.

[0006] WO 00/56891 relates to speculative human transmembrane proteins. It discloses a sequence which corresponds to a ceramidase, but without assigning functionality to it. Koch, Jürgen et al. in Journal of Biological Chemistry (271) 33110-33115, Rosenberg A. in Proceedings of the Federation of European Biochemical Societies 1980, L. Babab Sama et al. in Journal of Biological Chemistry (274), pages 27948-27955, Jada Y. et al. in Journal of Biological Chemistry (270), pages 12677-12684, also report on ceramidases and their characterization.

[0007] According to the invention, a ceramidase is provided having the following structural motif

Z¹-X1-H-X2-T-L-X2-X2-X2-X2-Q-X2-X2-D-E,-Z²

[0008] wherein the X1 position is an aromatic amino acid (F, Y or W), all X2 positions may be any independent amino acids, and Z¹ and Z² may be any polypeptides.

[0009] The proteins claimed according to the invention contain the motif mentioned in claim 1. These include proteins which have been modified in the side chains, especially with phosphorylations, glycosylations, amidizations and other derivatizations in the side chains. In addition, the skilled person will recognize that fragments which also ensure the biological functions of the proteins according to the invention can be prepared by modifications in the primary structure. These include, for example, fragmentations in the region around the motif claimed according to the invention. The corresponding biologically active fragments can be readily established by the skilled person by appropriate experiments. These include, for example, site-directed mutagenesis by means of which structural variants which also have biological activity can be prepared. In addition, in terms of protein chemistry, exchanges of amino acids or sequences or motifs within the primary structure also suggest themselves. Such exchanges are well-known to the skilled person and comprise, for example, conservative exchanges in which, for example, serine is exchanged against threonine. Of course, there are further groups known to the skilled person which are candidates for exchange. For example, the members of the groups of non-polar amino acids, polar amino acids, aromatic amino acids are respectively interchangeable without any substantial changes in biological function to be expected.

[0010]FIG. 1 shows the result of Northern blot analysis. Part A (left) shows that no signal from ceramidase can be seen in a wide variety of human tissues. Part B (right) shows that a strong signal can be seen in skin RNA, which signal is absent in the human cell lines shown.

[0011]FIG. 2 shows the result of a quantitative PCR analysis of the skin-specific ceramidase K1 and in comparison to ceramidase K2. The expression level of ceramidase K1 in the skin is age-dependent; in the skin of a 68-year-old human, a stronger signal can be observed than in the skin of a 28-year-old human. Ceramidase K2 does not exhibit any age dependence.

[0012] Preferred are transmembrane ceramidases.

[0013] Preferred ceramidases have the following sequence: Ceramidase K1 (human protein) SEQ ID NO: 1; Ceramidase K2 (human protein) SEQ ID NO: 2; Ceramidase K4 (human protein) SEQ ID NO: 3;

[0014] The invention also relates to nucleic acids coding for ceramidase, especially those having the sequences: Ceramidase K1 SEQ ID NO: 4; Ceramidase K2 SEQ ID NO: 5; Ceramidase K4 SEQ ID NO: 6.

[0015] The invention also relates to a nucleic acid which is complementary to these nucleic acids.

[0016] A further aspect of the invention is a medicament, cosmetic or diagnostic agent containing the ceramidase according to the invention or a nucleic acid according to the invention, excluding the ceramidase SEQ ID NO: 2, i.e., SEQ ID NO: 5.

[0017] The medicaments, cosmetic and diagnostic agents are suitable for the diagnostics of diseases, for the treatment or prevention of diseases associated with a ceramidase defect, especially in connection with diseases accompanied by a defective cell proliferation (e.g., cancer), diseases accompanied by a defect in the ceramide layer of the skin, such as neurodermitis, eczema, psoriasis, and for the well-aimed affection of the permeability barrier by ceramidase or ceramidase activators, e.g., for the transcutaneous administration of substances.

[0018] The gene for ceramidase K4 resides on chromosome 2 in the region 2q33q34. This region also contains the gene for the skin diseases “lamellar ichthyosis ICR2B”.

[0019] The ceramidase K4 according to the invention is particularly suitable for the diagnostics and therapy of this latter disease, with which it is presumably connected in a causal relationship.

[0020] The invention also relates to a cell line which overexpresses the ceramidases according to the invention, and to a transgenic animal with overexpression or gene deficiency or gene defect for the ceramidases according to the invention.

EXAMPLES

[0021] Cloning of the Whole cDNA:

[0022] The cDNA of Cdase1 was amplified by means of PCR. 5 μg of human skin RNA, which had been previously subjected to reverse transcription, served as the template. The following primers were used for amplification: cer1 atg2 s: caagATGCCTAGCATCTTCGCC Seq. ID No 7 cert e2 as: caggtctcagcagtccttgtcatc Seq. ID No 14

[0023] The amplified cDNA was subcloned, and the sequence was subsequently verified.

[0024] Tissue Distribution

[0025] The tissue distribution of Cdase1 was analyzed by the Northern blot technique. Thus, there was used, on the one hand, a commercially available blot (Clontech Laboratories Inc., Catalog #: 7780-1), and on the other hand, a blot prepared from RNA from cell lines and human skin (1 μg each of poly-A⁺ RNA). The first 668 bp of the cDNA was used as a probe. The cDNA fragment was labeled radioactively. Hybridization took place over night at 65° C. The radioactive signals were measured by means of the Cyclone Storage Phosphor System (both supplied by Packard Instrument Company, Dreieich, Germany) and evaluated with the program OptiQuant. The blots were normalized with either β-actin or GAPDH.

[0026] Cell Lines Which Stably Overexpress Cdase1:

[0027] The whole cDNA was cloned into a eukaryotic expression vector under the control of CMV promoter. HEK293 cells were electroporated with the construct and subsequently selected with G418. Cell clones which survived the selection were examined for Cdase1 overexpression.

[0028] Age-Dependent Expression of Cdase1:

[0029] The expression levels in young and old skin were established by means of real time PCR using Taq-man (Perkin Elmer). GAPDH served as an internal standard.

[0030] The Following Primers Were Employed: CER1.SEQ-456F: GCA TTG CCC TGC ACA TTC T Seq ID No 8 CER1.SEQ-526R: GTG CCG AAG CTC CTT ATT GC Seq. ID No 9 tmcer1: CATCGTGTGCCAGGABTACAGGAAGACC [5′]6_FAM [3′]TAMRA Seq. ID No 10 GAPDHS: GAAGGTGAAGGTCGGAGT Seq. ID No 11 GAPDHR: GAAGATGGTGATGGGATTTC Seq. ID No 12 GAPDHT: CAAGCTTCCCGTTCTCAGCC [5′]6_FAM [3′]TAMRA Seq. ID No 13

[0031]

1 14 1 264 PRT Homo sapiens 1 Met Pro Ser Ile Phe Ala Tyr Gln Ser Ser Glu Val Asp Trp Cys Glu 1 5 10 15 Ser Asn Phe Gln Tyr Ser Glu Leu Val Ala Glu Phe Tyr Asn Thr Phe 20 25 30 Ser Asn Ile Pro Phe Phe Ile Phe Gly Pro Leu Met Met Leu Leu Met 35 40 45 His Pro Tyr Ala Gln Lys Arg Ser Arg Tyr Ile Tyr Val Val Trp Val 50 55 60 Leu Phe Met Ile Ile Gly Leu Phe Ser Met Tyr Phe His Met Thr Leu 65 70 75 80 Ser Phe Leu Gly Gln Leu Leu Asp Glu Ile Ala Ile Leu Trp Leu Leu 85 90 95 Gly Ser Gly Tyr Ser Ile Trp Met Pro Arg Cys Tyr Phe Pro Ser Phe 100 105 110 Leu Gly Gly Asn Arg Ser Gln Phe Ile Arg Leu Val Phe Ile Thr Thr 115 120 125 Val Val Ser Thr Leu Leu Ser Phe Leu Arg Pro Thr Val Asn Ala Tyr 130 135 140 Ala Leu Asn Ser Ile Ala Leu His Ile Leu Tyr Ile Val Cys Gln Glu 145 150 155 160 Tyr Arg Lys Thr Ser Asn Lys Glu Leu Arg His Leu Ile Glu Val Ser 165 170 175 Val Val Leu Trp Ala Val Ala Leu Thr Ser Trp Ile Ser Asp Arg Leu 180 185 190 Leu Cys Ser Phe Trp Gln Arg Ile His Phe Phe Tyr Leu His Ser Ile 195 200 205 Trp His Val Leu Ile Ser Ile Thr Phe Pro Tyr Gly Met Val Thr Met 210 215 220 Ala Leu Val Asp Ala Asn Tyr Glu Met Pro Gly Glu Thr Leu Lys Val 225 230 235 240 Arg Tyr Trp Pro Arg Asp Ser Trp Pro Val Gly Leu Pro Tyr Val Glu 245 250 255 Ile Arg Gly Asp Asp Lys Asp Cys 260 2 267 PRT Homo sapiens 2 Met Ala Pro Ala Ala Asp Arg Glu Gly Tyr Trp Gly Pro Thr Thr Ser 1 5 10 15 Thr Leu Asp Trp Cys Glu Glu Asn Tyr Ser Val Thr Trp Tyr Ile Ala 20 25 30 Glu Phe Trp Asn Thr Val Ser Asn Leu Ile Met Ile Ile Pro Pro Met 35 40 45 Phe Gly Ala Ile Gln Ser Val Arg Asp Gly Leu Glu Lys Arg Tyr Ile 50 55 60 Ala Ser Tyr Leu Ala Leu Thr Val Val Gly Met Gly Ser Trp Cys Phe 65 70 75 80 His Met Thr Leu Lys Tyr Glu Met Gln Leu Leu Asp Glu Leu Pro Met 85 90 95 Ile Tyr Ser Cys Cys Ile Phe Val Tyr Cys Met Phe Glu Cys Phe Lys 100 105 110 Ile Lys Asn Ser Val Asn Tyr His Leu Leu Phe Thr Leu Val Leu Phe 115 120 125 Ser Leu Ile Val Thr Thr Val Tyr Leu Lys Val Lys Glu Pro Ile Phe 130 135 140 His Gln Val Met Tyr Gly Met Leu Val Phe Thr Leu Val Leu Arg Ser 145 150 155 160 Ile Tyr Ile Val Thr Trp Val Tyr Pro Trp Leu Arg Gly Leu Gly Tyr 165 170 175 Thr Ser Leu Gly Ile Phe Leu Leu Gly Phe Leu Phe Trp Asn Ile Asp 180 185 190 Asn Ile Phe Cys Glu Ser Leu Arg Asn Phe Arg Lys Lys Val Pro Pro 195 200 205 Ile Ile Gly Ile Thr Thr Gln Phe His Ala Trp Trp His Ile Leu Thr 210 215 220 Gly Leu Gly Ser Tyr Leu His Ile Leu Phe Ser Leu Tyr Thr Arg Thr 225 230 235 240 Leu Tyr Leu Arg Tyr Arg Pro Lys Val Lys Phe Leu Phe Gly Ile Trp 245 250 255 Pro Val Ile Leu Phe Glu Pro Leu Arg Lys His 260 265 3 273 PRT Homo sapiens 3 Met Gly Ala Pro His Trp Trp Asp Gln Leu Gln Ala Gly Ser Ser Glu 1 5 10 15 Val Asp Trp Arg Glu Asp Asn Tyr Thr Ile Val Pro Ala Val Ala Glu 20 25 30 Phe Tyr Asn Met Ile Ser Asn Val Leu Phe Phe Ile Leu Pro Pro Ile 35 40 45 Cys Met Cys Leu Phe Arg Gln Tyr Ala Thr Cys Phe Asn Ser Gly Ile 50 55 60 Tyr Leu Ile Trp Leu Leu Val Val Ala Gly Ile Gly Ser Val Tyr Phe 65 70 75 80 His Ala Thr Leu Ser Phe Leu Gly Gln Met Leu Asp Glu Leu Ala Val 85 90 95 Leu Trp Val Leu Met Cys Ala Ser Val Met Trp Phe Pro Arg Arg Tyr 100 105 110 Leu Pro Lys Ile Phe Arg Asn Asp Gln Gly Arg Phe Lys Val Val Cys 115 120 125 Val Leu Ser Ala Val Met Thr Cys Leu Ala Phe Val Lys Pro Ala Ile 130 135 140 Asn Asn Ile Ser Leu Met Thr Leu Gly Val Pro Cys Ala Ala Leu Leu 145 150 155 160 Ile Thr Glu Leu Lys Arg Cys Asp Asn Met Arg Val Phe Lys Leu Gly 165 170 175 Leu Phe Ser Gly Leu Trp Trp Thr Leu Ala Leu Phe Cys Trp Ile Ser 180 185 190 Asp Arg Ala Phe Cys Glu Leu Leu Ser Ser Phe Asn Phe Pro Tyr Leu 195 200 205 His Cys Met Trp His Ile Leu Ile Cys Leu Ala Ala Tyr Leu Gly Cys 210 215 220 Val Cys Phe Ala Tyr Phe Asp Ala Ala Ser Glu Ile Pro Glu Gln Gly 225 230 235 240 Pro Val Ile Lys Phe Trp Pro Ser Glu Lys Trp Ala Phe Ile Gly Val 245 250 255 Pro Tyr Val Ser Leu Leu Cys Ala Asn Lys Lys Ser Ser Val Lys Thr 260 265 270 Thr 4 792 DNA Homo sapiens 4 atgcctagca tcttcgccta tcagagctcc gaggtggact ggtgtgagag caacttccag 60 tactcggagc tggtggccga gttctacaac acgttctcca atatcccctt cttcatcttc 120 gggccactga tgatgctcct gatgcacccg tatgcccaga agcgctcccg ctacatttac 180 gttgtctggg tcctcttcat gatcataggc ctgttctcca tgtatttcca catgacgctc 240 agcttcctgg gccagctgct ggacgagatc gccatcctgt ggctcctggg cagtggctat 300 agcatatgga tgccccgctg ctatttcccc tccttccttg gggggaacag gtcccagttc 360 atccgcctgg tcttcatcac cactgtggtc agcacccttc tgtccttcct gcggcccacg 420 gtcaacgcct acgccctcaa cagcattgcc ctgcacattc tctacatcgt gtgccaggag 480 tacaggaaga ccagcaataa ggagcttcgg cacctgattg aggtctccgt ggttttatgg 540 gctgttgctc tgaccagctg gatcagtgac cgtctgcttt gcagcttctg gcagaggatt 600 catttcttct atctgcacag catctggcat gtgctcatca gcatcacctt cccttatggc 660 atggtcacca tggccttggt ggatgccaac tatgagatgc caggtgaaac cctcaaagtc 720 cgctactggc ctcgggacag ttggcccgtg gggctgccct acgtggaaat ccggggtgat 780 gacaaggact gc 792 5 801 DNA Homo sapiens 5 atggctccgg ccgcggaccg agagggctac tggggcccca cgacctccac gctggactgg 60 tgcgaggaga actactccgt gacctggtac atcgccgagt tctggaatac agtgagtaac 120 ctgatcatga ttatacctcc aatgttcggt gcaattcaga gtgttagaga cggtctggaa 180 aagcggtaca ttgcttctta tttagcactc acagtggtag gaatgggatc ctggtgcttc 240 cacatgactc tgaaatatga aatgcagcta ttggatgaac tcccaatgat atacagctgt 300 tgcatatttg tgtactgcat gtttgaatgt ttcaagatca agaactcagt aaactaccat 360 ctgcttttta ccttagttct attcagttta atagtaacca cagtttacct taaggtaaaa 420 gagccaatat tccatcaggt catgtatgga atgttggtct ttacattagt acttcgatct 480 atttatattg ttacatgggt ttatccatgg cttagaggac tgggttatac atcattgggt 540 atatttttat tgggattttt attttggaat atagataaca tattttgtga gtcactgagg 600 aactttcgaa agaaggtacc acctatcata ggtattacca cacaatttca tgcatggtgg 660 catattttaa ctggccttgg ttcctatctt cacatccttt tcagtttgta tacaagaaca 720 ctttacctga gatataggcc aaaagtgaag tttctctttg gaatctggcc agtgatcctg 780 tttgagcctc tcaggaagca t 801 6 822 DNA Homo sapiens 6 atgggcgccc cgcactggtg ggaccagctg caggctggca gctcggaggt ggactggcgc 60 gaggacaact acaccatcgt gcctgctgtc gccgagttct ataacatgat cagcaatgtc 120 ttatttttca ttttaccgcc catctgcatg tgcttgtttc gtcagtatgc aacatgcttc 180 aacagcggca tctacttaat ctggctcttg gttgtagcgg gaattggatc cgtctacttc 240 catgcaaccc ttagtttcct gggtcagatg cttgatgaac ttgcagtcct ttgggttctg 300 atgtgtgctt cggtcatgtg gttccccaga aggtatctac caaagatctt tcggaatgac 360 cagggtaggt tcaaggtggt ggtctgtgtc ctgtctgcag ttatgacgtg cctggcattt 420 gtcaagcctg ccatcaacaa catctctctg atgaccctgg gagttccttg cgctgcactg 480 ctcatcacag agctaaagag gtgtgacaac atgcgtgtgt ttaagctggg cctcttctcg 540 ggcctctggt ggaccctggc cctgttctgc tggatcagtg accgagcttt ctgcgagctg 600 ctgtcatcct tcaacttccc ctacctgcac tgcatgtggc acatcctcat ctgccttgct 660 gcctacctgg gctgtgtatg ctttgcctac tttgatgctg cctcagagat tcctgagcaa 720 ggccctgtca tcaaattctg gcccagcgag aaatgggcct tcattggtgt cccctatgtg 780 tccctcctgt gtgccaacaa gaaatcatca gtcaagacca cg 822 7 22 DNA Artificial Sequence Primer 7 caagatgcct agcatcttcg cc 22 8 19 DNA Artificial Sequence Primer 8 gcattgccct gcacattct 19 9 20 DNA Artificial Sequence Primer 9 gtgccgaagc tccttattgc 20 10 28 DNA Artificial Sequence Primer 10 catcgtgtgc caggabtaca ggaagacc 28 11 18 DNA Artificial Sequence Primer 11 gaaggtgaag gtcggagt 18 12 20 DNA Artificial Sequence Primer 12 gaagatggtg atgggatttc 20 13 20 DNA Artificial Sequence Primer 13 caagcttccc gttctcagcc 20 14 24 DNA Artificial Sequence Primer 14 caggtctcag cagtccttgt catc 24 

1. A ceramidase having the following structural motif Z¹-X1-H-X2-T-L-X2-X2-X2-X2-Q-X2-X2-D-E,-Z² wherein the X1 position is an aromatic amino acid (F, Y or W), all X2 positions may be any independent amino acids, and Z¹ and Z² may be any polypeptides.
 2. The ceramidase according to claim 1, characterized by comprising the sequences SEQ ID NOS: 1, 2 and/or
 3. 3. A nucleic acid coding for ceramidase according to either of claims 1 or 2, especially a nucleic acid having the sequence of SEQ ID NOS: 4, 5 and/or
 6. 4. A nucleic acid, characterized by being complementary to the nucleic acid according to claim
 3. 5. A medicament, cosmetic or diagnostic agent containing the ceramidase according to claim 1 or 2 or the nucleic acid according to claim 3 or
 4. 6. Use of the medicament or diagnostic agent according to claim 5 for the diagnostics of diseases associated with a ceramidase defect, for the treatment or prevention of diseases associated with a ceramidase defect, especially in connection with diseases accompanied by a defective cell proliferation (e.g., cancer), diseases accompanied by a defect in the ceramide layer of the skin, such as neurodermitis, eczema, psoriasis, and for the well-aimed affection of the permeability barrier by ceramidase or ceramidase activators, e.g., for the transcutaneous administration of substances.
 7. Use of the medicament or diagnostic agent according to claim 5 for the diagnostics of ichthyosis, especially lamellar ichthyosis ICR2B.
 8. Use of the ceramidase according to claim 1 or 2 as a cosmetic agent.
 9. A transgenic animal exhibiting overexpression (gain of function) or gene deficiency or gene defect (loss of function) for a ceramidase according to either of claims 1 or
 2. 10. A cell line, characterized by overexpressing a ceramidase according to either of claims 1 or
 2. 